The present invention relates to an opaque film of thermoplastic organic material and more particularly to an opaque heat-sealable film of thermoplastic material containing a finely distributed solid filler material.
Films which are sufficiently impermeable to light, fat-repellent, and impermeable to water-vapor are required for many purposes, especially for packaging foodstuffs. The known opaque plastic films have these properties, but are incapable of being heat-sealed and have only mat, dull surfaces without the desired lustre. Furthermore, their printability is not particularly good.
A great number of processes and compounds have been disclosed which may be used for the preparation of a heat-sealable layer on a plastic film, but it must be expected that they will not improve the dull appearance of an opaque plastic film and that the plastic film will lose its white look.